The present invention relates to low molecular weight derivatives containing more than one aldehyde group. It also relates to the low molecular weight acetal derivatives used in the preparation thereof. It further relates to processes for introducing aldehyde groups into low molecular weight compounds.
There is a need for formaldehyde-free crosslinking agents (i.e., agents that do not release formaldehyde on crosslinking) particularly for use in durable press and corrugating adhesive applications.
U.S. Pat. No. 4,447,594 (issued May 8, 1984 to S. M. Cohen et al.) discloses polyaldehyde adducts of isocyanuric acid and acrolein. Preparation of these adducts is described in U.S. Pat. No. 4,326,057 (issued Apr. 20, 1982 to S. M. Cohen et al.). These adducts or their hemiacetals are used in heat-curable coating compositions containing a polyunsaturated ester of an ethylenically unsaturated acid (e.g., acrylic acid, methacrylic acid, or itaconic acid), a polyhydric alcohol, and a free radical or ionic initiator.
U.S. Pat. No. 4,293,693 (issued Oct. 6, 1981 to S. M. Cohen et al.) discloses isocyanuric aldehydes also referred to as (3-oxopropyl)isocyanurates, which have the formula ##STR1##
These polyaldehydes are used in the preparation of hemiacetals, which are themselves useful as polymerizing or crosslinking agents for polyfunctional compounds containing hemiacetal reactive groups (e.g., amines, amides, alcohols, thiols, and oxiranes).